Studies of Dietary Piperazine, Phenothiazine, and Dibutyltin Dilaurate

YOLK mottling first received extensive study shortly after Nicarbazin was placed on the market; among the first studies reporting Nicarbazin mottling were those of Baker et al. (1956) and Polin and Porter (1956). Several reports followed and Nicarbazin is now carefully kept out of layer feeds, but the problems it created have stimulated the interest in yolk defects. However, occasional severe cases of mottling have resulted in considerable economic loss to poultrymen and a corresponding inconvenience and loss to handlers and retailers. Beane et al. (1960) reported a brownish darkening of yolks due to the feeding of piperazine citrate. This report and field cases of yolk mottling in Florida and the Midwest prompted the initiation of the study herein reported. Recently, Beane et al. (1965) reported that three forms of piperazine (citrate, dihydrochloride, and sulfate) caused significantly greater yolk discoloration than that of the controls. This discoloration has been described …